The present invention relates to a non-volatile memory device and a method of operating the same, in which program voltages of a non-volatile memory device are controlled variably according to a program/erase operation count.
Recently, there is an increasing demand for non-volatile memory devices which can be electrically programmed and erased, and do not need the refresh function of rewriting data at regular intervals.
When using such a non-volatile memory device, program/erase operations are continuously repeated. As the repetition number is increased, the program speed of each memory cell increases.
In order to prevent this phenomenon and make the program speed constant, a method of applying a low program start voltage at the time of an initial program operation is frequently used. In other words, according to this method, in performing the program operation using an Incremental Step Pulse Program (ISPP) method, a program start voltage lower than a program voltage at normal operation is applied to prevent the program speed from increasing.
However, in this case, since the program start voltage is low, there is a problem in that the time required for programming from the start step to other steps is lengthened.
Accordingly, there is a need for a non-volatile memory device that is able to prevent the program speed increase phenomenon according to the repetition of the program/erase operations while not increasing overall program time.